Often this consisted of fragmentary tales related by some wandering Indian concerning the strange things he had encountered far away toward the land of the setting sun. Allowances were made for the superstition of the natives when a record was kept of these tales; but often there seemed a shred of truth behind it all which could be made to serve the purposes of the daring explorers.

So deeply interested was Captain Clark in some work on which he was engaged, and which seemed to be in the nature of making a new map of the country through which they had already passed, that he had actually paid no attention to all the shouting outside.

When his colleague came in, accompanied by the two boys, Captain Clark realized for the first time that something out of the ordinary must have happened.

He listened intently as the story of Mayhew’s strange loss was unfolded, asked a number of questions that put him in possession of all the known facts, and then gave his conclusion.

“I am of the same opinion as the rest of you!” he declared. “It must have been the work of the men who would profit should that paper fail to reach the Armstrongs by spring; this French trader, François Lascelles, and his equally unscrupulous son, Alexis.”

“But to think of them following us all the way to this point! It seems almost impossible,” urged the other captain.

“Why should it be considered so?” asked the soldier, who appeared to grasp the salient points much easier than the President’s private secretary had done. “We have encountered no difficulties that a party of hardy voyageurs and trappers might not have overcome. Besides, it is quite possible that this same trader may have been in this country before now. The French were in possession of the great Mississippi Valley all the way down to the Gulf many years before it came into the hands of the United States Government. They must have had trading posts far to the west, and their half-breed trappers have taken beaver and all other fur-bearing animals from the streams of the Far Northwest.”

“You are right, Captain Clark,” said the other, warmly “and, after hearing your reasonable explanation, I can well believe that these men are no strangers to the region of the headwaters of the Missouri.”

“I also agree with Mayhew regarding the camp having been watched,” continued the soldier, gravely. “They suspected we would be sending back a report of our progress, and surmised also that these brave boys would either themselves carry their paper to their homes or else give it into the keeping of our messengers. Just how they knew that Mayhew was carrying their document, and not either of the other messengers, I cannot say, but it seems that they managed to do so.”